Sheet metal forming apparatus



Dec. 5, 1961 r. B. CAMPBELL SHEET METAL FoRMTNG APPARATUS 3 Sheets-Sheet 1 Filed June 30, 1959 ATTORNEY 5' Dec. 5, 1,961 T. B. CAMPBELL SHEET METAL FoRMTNG APPARATUS 5 Sheets-Sheet 2 Filed June 30, 1959 INV EN TOR 7.' BRUCE CAMPBELL ATTORNEYS Dec. 5, 1961 r. B. CAMPBELL 3,011,533

SHEET METAL FORMING APPARATUS Filed June 30, 1959 5 Sheets-Sheet 5 INV ENTOR l r Bnl/0E GAM/BELL BY l/ ATTORNEYS United States Patent G 3,011,538 SHEET METAL FORMING APPARATUS Thomas Bruce Campbell, Box 235, West Middlesex, Pa. Filed dune 30, 1959, Ser. No. 823,874 9 Claims. (Cl. 153-75) This invention relates to metal working and more particularly to an apparatus for forming longitudinal corrugations or other shapes in a strip of sheet metal of any desired length.

As is well known, `it is customary in the formation of sheet metal shapes to pass a continuous strip of such sheet metal through a pair of forming rolls or a series of such rolls and after completion of the roll forming operation to cut oil the sheet metal to the desired length by a suitable shearing mechanism. Since in this type of sheet metal forming operation the sheet metal is continuously moving, the shear must be of the so-called ilying type and such a shear is relatively complex and costly and furthermore, rolling mills for this type of operation are also relatively costly. Where a large quantity of sheet metal is to be formed to a particular` shape, the high cost of rolling mills for this purpose are justified, since this type of mill permits high production speed andralso where relatively large quantities are to be processed separate mills for processing different shapes may be justified or the time required for changing rolls, together with the cost of such replacement rolls may also be justiiied.

However, in cases where production runs are limited to small quantities of sheet material, the use of costly rolling mills and shearing apparatus is-not justified and as a result, sheet metal forming operations have been largely restricted to large shops. There are many cases, however, where a relatively small quantity of formed sheet metal is required and these forming operations could advantageously be carried out in small shops if it were possible to provide a forming apparatus of relatively simple constructionl and low cost and also one which might easily be converted for forming different shapes in the sheet meal without the necessity for providing costly rolls of different shapes and also absorbing the cost of roll changes necessitated by changes in shapes to be produced. It is also essential if operations of this type are to be carried out in a small shop, to provide means for cutting the sheet metal tothe desired length which will be relatively simple and inexpensive. The provision of an apparatus of this type would enable small shops to produce formed sheet metal at a relatively low cost which would enable the economical 'production of small quantities of formed sheet metal thereby making available a new eld for small producers which would not materially aifect the production of large mills.

It is accordingly an object of theinvention to provide a sheet metal forming apparatus which may be economically utilized Ifor the formation of relatively small quantities of sheet metal in strip form.

A further object of the invention is sheet metal forming apparatus which may be manually or power operated and which may be utilized to form a continuous strip of sheet metal and also including means for cutting off the sheet metal to the desired length.

A still further object of the invention is the provision of a sheet metal forming apparatus in which the forming operation is carried out while the sheet is at rest and in which means is provided for intermittently feeding the sheet of material between forming operations.

Another obpect of the invention is the provision of a sheet metal forming apparatus for sheet metal in which the forming operation is accomplished by upper and lower 'platens having mating die or forming surfaces which may be conveniently changedrin order to change the particular shape being formed in the sheet metal.

the provision Vof a Naice sheet metal forming apparatus for forming longitudinal corrugations or other shapes in a continuous strip vof sheet metal in which the sheet metal moves intermittently through the apparatus and in which means in the form of a stationary shear is provided for cutting the strip material to the desired length during a period when the strip material is at rest.

A further object of the invention is the provision of a sheet metal forming apparatus for forming longitudinalv corrugations or other shapes in a continuous strip of sheet metal, such apparatus including an upper platen pivotally movable with `respect to a xed lower platen and in which feeding means for the strip material is provided, the operation of such feeding means being in timed relation to the pivotal movement ofthe upper platen.

A still further object of the invention is the provision of a sheet metal forming apparatus for forming longitudinal corrugations or other shapes in a continuous strip of sheet metal, such apparatus including an upper platen pivotally movable with respect to a ixed lower platen and in which vibrators are provided on the upper and lower platens in order to facilitate the forming operation and also in order to facilitate stripping of the sheet metal from the forming portions of the upper and lower platens. Further objects `and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings wherein:

FIGURE 1 is a side elevational View of a sheet metal forming apparatus constructed in accordance with this l invention and showing the upper platen in forming position in full lines and in inoperative position for permitting feeding of the sheet metal in dotted lines;

FIG. 2 a top plan view of the sheet metal forming apparatus shown in FIG. l;

FIG. 3 a fragmentary sectional view taken substantially on the line 3 3 of FIG. 1 and showing the mechanism for operating the upperforming platen and for operating the sheet metal feeding mechanism;

FIG. 4 an end elevational View of the sheet metal forming apparatus shown inFIG. 1 with certain parts omitted and showing in detail the structure of the shear for cutting oif the sheetmetal to the desired length;

FIG. 5 a bottom plan view of the upper forming platen; and j FIG. 6 a side elevational view similar to FIG. 1 and showing a sheet metal lforming apparatus constructed in accordance with this invention and provided with vibrators on the upper and lower forming platens.

With continued reference to the drawings, there is shown a sheet metal forming apparatus constructed in accordance with this invention and which may well comprise a frame composed of upright members 10, 11 and Y 12 connected by suitable cross members, not shown, the uprights 10, 11 and 12 serving to support a table 13, a portion of which is formed to provide a lower forming platen, the structure of which will be presently described.

With particular reference to FIGS. 1, 2, 3 and 5, `an upper forming platen 14 is provided in the form of a generally rectangular plate and arms 15 vand 16 extend rearwardly from the side edges of the plate and between the arms 15 and 16and extending forwardly from the rear edge 17 of the platen 14 is a generally V-shaped notch 18, the purpose of which will be later described.

On the lower surface of the platen 14 there is provided a pair of downwardly projecting longitudinally extending transversely spaced ribs 19 and 20 disposed at one side of the notch 18 and at the opposite side of the notch 1S there is a similar pair of ribs 21 and 22. The outer ribs 19 and 21 terminate at the rear edge 17 of the platen 14 and the forward ends 23 and 24 of the ribs 19 and 21 terminate at a point substantially midway of the length of the notch 1S in the platen 14. The rear ends 25 and 26 of Ithe ribs 20 and 22 terminate rearwardly of the outer end of the forward ends 23 and 24 of the ribs 19' and 21 and the forward ends 27 and 28 of the ribs 20l and 22 terminate forwardly of the forward end 29 of the notch 18. A central downwardly projecting rib 30 is provided o n the lower surface of the platen 14 and the rear end 31 of the rib 30 terminates at the forward edge of the notch 29 and the forward end 32 of the rib 39 terminates substantially at the forward edge 33 of the platen 14. As best shown in FIGS. 1 and 5, the forward ends 23 and 24 of the ribs 19 and 21, the forward ends 27 and 28 of the ribs 20 and 22 and the forward end 32 of the rib 30 are tapered and are also curved upwardly toward the lower surface of the platen 14.

The rear ends of the arms and 16 on the platen 14 are pivotally mounted on the uprights 12 by suitable pivot f pins 34 and 35 and in this manner the upper platen 14 is mounted for pivotal movement toward and away from the upper surface of the table 13. Operating means for the upper platen 14 is provided in the form of a crank shaft 36 rotatably mounted on the uprights 11 of the frame and the crank shaft 36 may be provided with crank throws 37 and 38 which are connected by connecting rods 39 and 40 to a shaft 41 extending through the connecting rods 39 and 40 and through ears 42 and 43 on the upper platen 14 adjacent the forward edge 33 thereof. The crank shaft 36-is provided outwardly of one of the uprights 11 with a crank arm 44, the purpose of which will be later described. In order to operate the crank shaft 36 and cause pivotal movement of the upper platen 14, there may be provided on the crank shaft 36 a crank 45 having a hand-engaging portion 46 which may be utilized to operate the crank shaft 36. This will provide for manual operation of the apparatus, but this is for illustrative purposes only and it is to `be understood that if desired, suitable power means may be substituted for the crank 45 in order to drive the crank shaft 36 from a suitable power source.

The upper surface of the table 13 may be provided with longitudinally extending grooves 47, 48, 49, 50 and 51, which grooves are located in such a manner as to mate with the downwardly extending ribs 19, 20, 21, 22 and 30 on the lower surface of the upper platen 14 and the rear ends of the grooves of the upper surface of the table 13 Iterminate at the rear end of such tables while the forward ends 52, 53, 54 and 55 of the grooves 47, 48, 50 and 51 respectively, terminate lforwardly of the ribs 21, 22, 19 and 20 respectively on the upper platen 14 and the forward end 56 of the groove 49 terminates forwardly of the forward end 32 of the rib 30. The grooves in the upper surface of the table 13 provide a lower forming platen cooperating with the ribs on the upper forming platen 14 and while such grooves are shown in the table top for purposes of illustration, it is to 'be understood that, if desired, a separate plate containing such grooves may be secured in a recess in the upper surface of the table 13 in order to facilitate changing of such lower platens in order to change the character of grooves or other formations to be impressed in the sheet metal. It is also to be understood that the upper platen 14 may be conveniently changed to provide another platen having different shaped ribs thereon, which, of course, must cofoperate with the mating grooves in -the lower platen in order to provide the desired sheet metal formation.

As best shown in FIGS. 1 and 2, a strip of sheet metal y57 may be supplied to the forming apparatus o-f this invention from a coil 5S which may be rotatably supported on cones 59 and 60 rotatably carried by shafts 61 and 62 respectively which in tu-rn are supported by upright blocks 63 and 64. The blocks 63 and 64 may be provided with set screws 65 `and 66 for engaging the shafts 61 and 62 respectively to hold the same in position or to permit movement of the shafts 61 and 62 to engage the cones 59 and 60 with the coil 58 of sheet metal 57.

'Feeding means for the sheet metal 57 may be provided in the form of a lower ro-ll 67 rotatably mounted in bearings 68 which in turn are slidably mounted in the uprights 10 of the frame. The bearings 68 may vbe urged upwardly by compression springs 69 and the upper surface of the roll 67 projects through an opening in the table 13 and is held in engagement with the lower surface of sheet metal 57 by the compression springs 69. An upper feeding roll 70 is rotatably mounted on the uprights 10 of the frame above the roll 67 and the upper surface of the sheet metal 57 is held in engagement with the surface of the feeding roll 70 by the upwardly spring urged -lower roll 6'7. A one-way clutch 71 of conventional type is provided on the shaft 72 supporting the upper roll 70 and an arm 73 is provided on the clutch 71, the arm 73 being pivotally connected at 74 to a link 75 which in turn is pivotally connected at 76 to the crank arm 44 fixed to the crank shaft 36. As a consequence, rotation of the crank shaft 36 will result in pivotally moving the upper platen 14 between the dotted and full line position shown in FIG. l and at the same time, the link 75 will cause the arm 73 to oscillate which will, through the one-way clutch 71, `move the upper feeding roll 30 through part of a revolution thereby moving the strip metal 57 a distance corresponding to the angular movement of the upper feeding roll 73. The relationship of the movement of the roll 70 to the pivotal movement of the upper platen 14 is such that movement of the strip metal 57 will only take place while the ribs on the lower surface of the upper platen 14 are disengaged from the strip of sheet metal 57.

Since sheet metal which has been formed by the ribs on the upper platen 14 tend to ,adhere to such upper platen in order to prevent upward movement of sheet metal upon upward movement of the upper platen 14, there is provided a combined guide and stripper 77 which is in the form of a at plate having a generally rectangular portion 78 secured to the frame-by suitable fastening means 79 with the rectangular portion 78 disposed between the arms 15 and 16 of the upper platen 14 and in spaced relation to the upper surface of the table 13. The combined guide and stripper 77 is also provided with a generally V-shaped portion 80 which extends forwardly into the notch 18 of t-he upper platen 14 and consequently7 the combined guide and stripper 77 will in no way interfere with the pivotal movement of the upper platen 14.

In the operation of the forming apparatus of this invention it is assumed that a coil S8 of suitable sheet metal material is rotatably mounted on the shafts 61 and 62 by the cones 59 and 60 and that the strip of sheet metal 57 extends between the roll 67 and upper feeding roll 70 and along the upper surface of the table 13 below the upper forming platen 14. Rotation of the crank shaft 36 will operate to periodically move the upper forming platen 14- toward and away from the table 13 kand the ribs on the lower surface `of the upper platen 14 will engage the strip of sheet metal 57 and force portions of the same into the grooves in the lower platen provided in the table 13. Continued rotation of the crank shaft 36 will oscillate the arm 73 and through the one* way clutch 71 move the upper feeding roll 70 through a portion of a revolution which will result in feeding the strip of sheet metal 57 along the table 13 toward the rear end thereof. Such movement of the strip material 57 takes place while the upper forming platen 14 is out of 4engagement with the strip material and consequently, repeated movements of the upper platen 14 will result in progressively forming corrugations in the sheet metal material 57 corresponding to the contour 'of the ribs and groovesk on the upper and lower platens. Obviously, such formation of the sheet metal takes' place progressively from the rear edge 17 of the upper platen v14- toward the front edge 33 thereof and the fact that the grooves in the table 13 or lower platen extend forwardly of the forward ends of the ribs on ythe upper platen 14, the sheet metal 57 will be gradually depressed into the grooves thereby preventing sudden deformation with the possibility of rupture of the material. As before stated, the ribs and grooves providing corrugations are shown for purposes of illustration only and it will be understood that the upper and lower platens may be changed to provide other desired shapes in the sheet metal.

Since the sheet metal 57 is provided in a continuous strip, it is obviously necessary to cut the same after formation to the desired length and for this purpose there is provided a shear, which as best shown in FIGS. l, 2 and 4, may well comprise a transverse blade 81 fixed to the rear end of the table 13 by suitable fastening means 82 and the blade 81 is provided with grooves S3, 84, 85, 86 and 87 in alignment with the grooves 47,. 48, 50, 51 and 49 respectively in the table 13. A blade 88 is fixed to an arm 89 by suitable securing means 90 and the arm 89 is pivotally mounted at 91 on a bracket 92 secured to the frame of the apparatus or to the table 13. The blade 88 is provided with downwardly projecting ribs 93, 94, 95, 96 and 97 which are disposed in alignment with the grooves 83, 84, 85, 86 and 87 respectively in Ithe fixed blade 81. In order to operate the arm 89 to move the blade 88 downwardly into cooperation with the xed.

blade 81 to provide a shearing action, there may be provided a hand lever 98 pivotally mounted at 99 on the frame or table 13 and a link 100 is pivotally connected at 101 to the hand lever 98 and is also pivotally connected at 102 to the free end of the arm 89 carrying the blade 88. 'As will be seen from an inspection of FIG. 4, the hand lever 98 and link 100 provide a toggle for moving the arm 89 and blade 88 toward the fixed blade 81 and since the formed sheet metal passes between the blades 81 and S8, operation of the movable blade 88 dowardly will cut the sheet metal by a shearing action and the provision of the grooves and ribs will prevent deformation of the formed sheet metal which will retain the desired' shape along the cut end thereof. Since the sheet metal strip 57 is at rest during a portion of the operation, the cutting means may be operated at this time, thereby precluding the necessity for providing a cutting or shearing apparatus which will operate on a moving strip of material. This materially reduces the cost of the apparatus as compared to a continuously running sheet metal forming apparatus.v

With particular reference to FIG. 6, there is shown a slightly modified form of the apparatus in which a suitable mechanical vibrating means indicated at 103 is mounted on the upper forming platen 14 and operation of the vibrator 103 will serve to facilitate formation of the corrugatio-ns or other shapes in the sheet metal and this vibratory action will also facilitate stripping of the sheet material from the ribs of the upper platen 14. Also, if desired, a similar mechanical vibrator 104 may be mounted on the table 13 and this vibrator will also operate to facilitate formation of the grooves or corrugations in sheet material and stripping of the same from the grooves in the table or lower platen. The specific structure of the vibrators 103 and 104 forms no lpart of the instant invention and any commercially available vibrator of this type will serve the purpose and consequently no detailed description of the construction of these vibrators is considered desirable or necessary.

It will be seen that by the above described invention there has been provided a relatively simple and inexpen.

sive sheet metal forming apparatus, which, however, is particularly suited for forming relatively small quantities of sheet material and which may be either hand or power operated to carry out the forming operation, together with simple hand operated cutting means for cutting the formed sheet material to the desired length. Obviously, the apparatus of this invention may be conveniently utilized in small shops for lling relatively small order for formed sheet metal, particularly in cases where the quantity involved would not warrant the installation -or operation of a conventional rolling mill.

It will be obvious to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is shown in the drawings and described in the specification, but only as indicated in the appended claims.

What is claimed is:

l. A sheet metal forming apparatus for forming longitudinal corrugations in a strip of sheet metal, said apparatus comprising a frame, a table mounted on said frame and providing a lower forming platen, an upper forming platen comprising a generally rectangular plate, an arm extending rearwardly from each side edge of said plate, a centrally disposed longitudinally extending generally V-shaped notch in the rear edge of said plate, saidk notch extending forward beyond the midpoint of said plate, a pair of downwardly projecting longitudinally extending transversely spaced ribs on the lower surface of said plate at opposite sides of said notch, the outer rib of each pair terminating at the rear edge of said plate and at a point substantially midway of the length of said notch, the inner rib of each pair terminating rearwardly of the forward end of the outer rib and forwardly of the forward end of said notch, a centrall downwardly projecting rib on the lower surface of said plate terminating at the forward end of said notch and at the forward edge of said plate, the forward ends of said ribs being tapered and curved upwardly toward the lower surface of said plate, means pivotally mounting the rear ends of said arms on said frame to mount said upper platen for pivotal movement toward and away from the upper surface of said lower platen, grooves in the upper surface of said lower platen mating with said ribs, said grooves terminating at the rear end of said table and extending forwardly of the forward ends of said ribs, a combined guide and stripper having a generally rectangular portion secured to said frame between said arms in spaced relation to said lower platen and a generally V-shaped portion extending forwardly into said notch, means for pivotally moving said upper platen comprising a crank shaft rotatably mounted on said frame, connecting rods connecting said crank shaft and the forward end of said upper platen, intermittent feeding means for sheet metal, whereby with a strip of sheet metal disposed between said upper and lower platen and upon rotation of said crank shaft land operation of said feeding means said upper platen will move toward saidlcwer platen and said ribs will progressively form corrugations in said sheet metal.

2. A sheet metal forming apparatus as defined in claim 1 in which vibrators are provided on said upperv and lower platens to facilitate formation of corrugations and stripping of the sheet metal from the ribs and grooves of the platens.

3. A sheet metal forming apparatus as defined in claim 1 in which said upper and lower platens are replaceable for forming different configurations in said sheet metal. Y

4. A sheet metal forming apparatus for forming longitudinal corrugations in a strip of sheet metal, said apparatus comprising a frame, a table mounted on said frame and providing a lower forming platen, an upper forming platen comprising a generally rectangular plate, an arm extending rearwardly from each side edge of said plate, a centrally disposed longitudinally extending generally V-shaped notch in the'rear edge of said plate, a pair of downwardly projecting longitudinally extending transversely spaced ribs on the lower surface of said plate at opposite sides of said notch, the outer rib of each pair terminating at the rear edge of said plate and at a point substantially midway of the length of said notch,

the inner rib of each pair terminating rearwardly of the forward end of the outer rib and forwardly of the forward end of said notch, a central downwardly projecting rib on the lower surface of said plate terminating at the forward end of said notch and at the forward edge of said plate, the forward ends of said ribs being tapered and curved upwardly toward the lower surface of said plate, means pivotally mounting the rear ends of said arms on said frame to mount said upper platen for pivotally movement toward and away from the upper stu'- face of said lower platen, grooves in the upper surface of said lower platen mating with said ribs', said grooves terminating at the rear end of said table and extending forwardly of the forward ends of said ribs, a combined guide and stripper having a generally rectangular portion secured to said frame between said arms in spaced relation to said lower platen and a generally 1J-shaped portion extending forwardly into said notch, means for pivotally moving said upper platen comprising a crank shaft rotatably mounted on said frame, connecting rods connecting said crank shaft and the forward end of said upper platen, intermittent feeding means for sheet metal, whereby with a strip of sheet metal disposed between said upper and lower platens and upon rotation of said crank shaft and operation of said feeding means said upper platen will move toward said lower platen and said ribs will progressively form corrugations in said sheet metal.

5. A sheet metal forming apparatus forming longitudinal corrugations in a strip of sheet metal, said apparatus comprising a frame, a table mounted on said frame and providing a lower forming platen, an upper forming platen comprising a generally rectangular plate, an arm extending rearwardly from the side edge of said plate, a centrally disposed longitudinally extending generally V- shaped notch in the rear edge of said plate, a pair of downwardly projecting longitudinally extending trans'- versely spaced ribs on the lower surface of said plate at opposite sides of said notch, the outer rib of each pair terminating at the rear edge of said plate and at a point substantially midway of the length of said notch, the inner rib of each pair terminating rearwardly of the forward end of the outer rib and forwardly of the forward end of said notch, a central downwardly projecting rib on the lower surface of said plate terminating at the forward end of said notch and at the forward edge of said plate, means pivotally mounting the rear ends of said cross arms on said frame to mount said upper platen for pivotal movement toward and away from the upper surface of said lower platen, grooves in the upper surface of said lower platen mating with said ribs, said grooves terminating at the rear end of said ta-ble and extending forwardly of the forward ends of said ribs, a combined guide and stripper having a generally rectangular portion secured to said frame between said arms in spaced relation to said lower platen and a generally V-shaped portion extending forwardly into said notch, means for pivotally moving said upper platen comprising a crank shaft rotatably mounted on said frame, connecting rods connecting said crank shaft and the forward end of said upper platen, intermittent feeding means' for sheet metal, whereby withV a strip of sheet metal disposed between said upper and lower platen and upon rotation of said crank shaft and operation of said feeding means said upper platen will move toward said lower platen and said ribs will progressively form corrugations in said sheet metal.

6. A sheet metal forming Iapparatus for forming longitudinal corrugations in a strip of sheet metal, said apparatus comprising a frame, a table mounted on said frame and providing a lower forming platen, an upper forming platencompn'sing a generally rectangular plate,

a centrally disposed longitudinally extending generally V-shaped notch in the rear edge of said plate, a pair of downwardly projecting longitudinally extending transversely spaced ribs on the lower surface of said plate at opposite sides of said notch, the outer rib of each pair terminating at the rear edge of said plate and at a point substantially midway of the length of said notch, the inner rib of each pair terminating rearwardly of theV forward end of the outer rib and forwardly of the forward end of said notch, a central downwardly projecting rib on the lower surface of said plate terminating at the forward end of said notch and at the forward edge of said plate, means pivotally mounting the rear ends of said upper platen o-n said frame for pivotal movement toward and away from the upper surface of said lower platen, grooves in the upper surface of said lower platen mating with said ribs, said grooves terminating at the rear end of said table and extending forwardly of the forward ends of said ribs, a combined guide and stripper having a generally rectangular portion secured to said frame in spaced relation to said lower platen and a generally V-shaped portion cxtending forwardly into said notch, means for pivotally moving said upper platen comprising a crank shaft rotatably mounted on said frame, connecting rods connecting said crank shaft and the forward end of said upper platen, intermittent feeding means for sheet metal, whereby with a strip of sheet metal disposed between said upper and lower platens and upon rotation of said crank shaft and operation of said feeding means said upper platen will move toward said lower platen and said ribs will progressively form corrugations in said sheet metal.

7. A sheet metal forming apparatus for forming longitudinal corrugations in a strip of sheet metal, said apparatus comprising a frame, a table mounted on said frame and providing a lower forming platen, an upper forming platen comprising a generally rectangular plate, a ccntrally disposed longitudinally extending V-shaped notch in the rear edge of said plate, a pair of downwardly projecting longitudinally extending transversely sp-aced ribs on the lower surface of said plate at opposite sides of said notch, the outer rib of each pair terminating at the rear edge 'of said plate and at a point substantially midway of the length of said notch, the inner rib of each pair terminating rearwardly of the forward end of the outer rib and forwardly of the forward end of said notch, a central downwardly projecting rib on the lower surface of said plate terminating at the forward end of said notch and at the forward edge of said plate, means pivotally mounting the rear end of said upper platen on said frame for pivotal movement toward and away from the upper surface of said lower platen, grooves in the upper surface of said lower platen mating with said ribs, said grooves terminating at the rear end of said table -and extending forwardly of the forward ends of said ribs, a combined guide Iand stripper secured to said frame in spaced relation to said lower platen and having a generally V-shaped portion extending forwardly into said notch, means for pivotally moving said upper platen comprising a crank shaft rotatably mounted on said frame, connecting rods connecting said crank shaft and the forwardrend of said upper platen, intermittent feeding means for sheet metal, whereby with a strip of sheet metal disposed between said upper and lower platens and upon rotation of said crank shaft and operation of said feeding means said upper platen will move toward said lower platen and said ribs will progressively form corrugations in said sheet metal.

8. A sheet metal forming apparatus for forming longitudinal corrugations in a strip of sheet metal, said ap paratus comprising a frame, a table mounted on said frame and providing a lower forming platen, an upper forming platen comprising a generally rectangular plate, a pair of downwardly projecting longitudinally extending transversely spaced ribs on the lower surface of said plate adjacent opposite sides of said plate, the outer rib of each pair terminating at the rear edge of said plate and at a point intermediate the length of said plate, the inner rib of each pair terminating rearwardly of the forward end of the outer rib andrearwardly of the 4forward. edge of said plate, a central downwardly projecting Vrib on the lower surface of said plate terminating rearwardly of the forward ends of said inner ribs and at the forward edge of said plate, means pivotally mounting the rear end of said upper plate on said frame for pivotall movement toward and away from the upper surface of said lower platen, grooves in the upper surface. of said lower platen mating with said ribs, said grooves terminating at the rear end of said table and extending forwardly of the forward ends of said ribs, means for pivotally moving said upper platen comprising a crank shaft rotatably mounted on said frame, connecting rods connecting said crank shaft and forward ends of said upper platen intermittent feeding means for sheet metal, whereby with a strip of sheet metal disposed between said upper and lower platens and upon rotation of said crank shaft and operation of said -feeding means said upper platen will move toward said lower platen and said ribs will progressively form corrugations in said sheet metal. f

9. A sheet metal forming apparatus for forming longitudinal corrugations in a strip of sheet metal, said apparatus comprising a frame, -a table mounted on said frame and providing a lower forming platen, an upper forming platen comprising -a generally rectangular plate, a pair of downwardly projecting longitudinally extending transversely spaced ribs on the lower surface of said plate adjacent the opposite sides of said plate, the outer rib of each pair terminating at the rear edge of said plate and at a point intermediate the length of said plate, the inner rib of each pair terminating rearwardly of the forward end of the outer -rib and rearwardly of the forward edge of Said plate, -a central downwardly projecting rib on the lower surface of said plate terminating rearwardly of the forward ends of said inner ribs and at the forward edge of said plate, means pivotally mounting the rear end of said upper platen on said frame for pivotal movement tow-ard and away from the uppersurface of said lower platen, grooves in the upper surface of said lower platen mating with said ribs, said grooves terminating at the rear end of said table and extending forwardly of the forward ends of said ribs, means for pivot-ally moving said upper platen comprising a crank shaft rotatably mounted, on said frame, connecting rods connecting said crank shaft and the forward end of said upper platen, intermittent feeding means iior sheet metal, whereby with a strip of sheet metal disposed between said upper and lower platens and upon rotation of said crank shaft and operation of said feeding means said upper platen will move toward said lower platen and said ribs will progressively form corrugations in said sheet metal.

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